Antiperspirant active compositions and manufacture thereof

ABSTRACT

An antiperspirant active composition comprising an aluminum salt, the aluminum salt (i) having an aluminum to chloride molar ratio of 0.3:1 to 3:1; and (ii) having a species of polyhydroxyoxoaluminum cation detectable it 76 ppm by  27 Al NMR that is present in a relative abundance on a  27 Al NMR spectrograph that is greater than an other polyhydroxyoxoaluminum cation detectable by  27 Al NMR. Also, disclosed are methods of making the antiperspirant active.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of application Ser. No.14/110,721, with a 371 entry date of 20 May 2014, which is a 371application of Application No. PCT/US2011/66012, filed on 20 Dec. 2011,which claims priority to U.S. Provisional Application No. 61/479,069,filed on 26 Apr. 2011, all of which are incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates to antiperspirant active compositions comprisingan aluminum salt and to methods of making an antiperspirant activecomposition.

BACKGROUND OF THE INVENTION

Antiperspirant salts, such as aluminum chlorohydrex (also calledaluminum chlorohydrex polymeric salts and abbreviated here as “ACH”) andaluminum zirconium glycine salts (abbreviated here as “ZAG”, “ZAGcomplexes” or “AZG”), are known to contain a variety of polymeric andoligomeric species with molecular weights (MW) of 100 Da-500,000 Da. Ithas been clinically shown that, in general, the smaller the species, thehigher the efficacy for reducing sweat.

In an attempt to increase the quality and quantity of smaller aluminumand/or zirconium species, a number of efforts have focused on: (1) howto select the components of ACH and ZAG that affect the performance ofthese materials; and (2) how to manipulate these components to obtainand/or maintain the presence of smaller types of these components. Theseattempts have included the development of analytical techniques toidentify the components. Size exclusion chromatography (“SEC”) or gelpermeation chromatography (“GPC”) are methods frequently used forobtaining information on polymer distribution in aluminum saltsolutions. With appropriate chromatographic columns, generally fivedistinctive groups of polymer species can be detected in commercial ACHand ZAG complexes appearing in a chromatogram as peaks 1, 2, 3, 4 and apeak known as “5, 6”, referred to hereinafter as Peak 5. Peak 1 containsthe larger Zr species (greater than 60 Angstroms). Peaks 2 and 3 containlarger aluminum species. Peak 4 contains smaller aluminum species(aluminum oligomers, or small aluminum clusters) and has been correlatedwith enhanced antiperspirant efficacy for both Al and Al/Zr salts. Peak5 contains the smallest and most acidic aluminum species. Variousanalytical approaches for characterizing the peaks of ACH and varioustypes of ZAG actives are found in “Antiperspirant Actives—EnhancedEfficacy Aluminum-Zirconium-Glycine (AZG) Salts” by Dr. Allan H.Rosenberg (Cosmetics and Toiletries Worldwide, Fondots, D. C. ed.,Hertfordshire, UK: Aston Publishing Group, 1993, pages 252, 254-256).

Attempts to activate antiperspirant salts to produce materials havingimproved efficacy have included developing processes for obtainingcomposition having large amounts of Peak 4,

The Applicant's earlier WO-A-2009/076591 discloses, inter alia, anantiperspirant composition having a composition with little or no Peak 3and optionally little or no Peak 5. However, there is still a need foryet further improved antiperspirant compositions.

Solutions of partially neutralized aluminum are known to contain avariety of hydrolytic Al species. The identity and distribution of thesevarious forms depends on the hydrolysis ratio (i.e. the OH:Al molarratio), the Al precursor and the choice of the reaction condition. Inthe field of antiperspirant (AP) technology, SEC chromatography is thetraditional method used for elucidating the distribution of these Alspecies. Conventional SEC physically separates Al species into domainswhich are subsequently measured using a concentration detector. It isgenerally recognized that at least five domains of Al species can bedifferentiated by size-exclusive chromatography. These domains arecommonly referred to Peak 1, Peak 2, Peak 3, Peak 4, and Peak 5, whereincreasing peak number indicates smaller relative size of the elutingspecies. Peak 4 and Peak 5 have been implicated as highly efficacious Aldomains for antiperspirants. Monomeric Al and low oligomers, are knownto elute under Peak 5. Oligomeric polyhydroxyoxoaluminum cations eluteunder Peak 4.

It is well known in the art that such a variety of hydrolytic Al speciesexists and that it is possible to distinguish large aqueous aluminumhydroxide molecules using spectroscopic methods such as ²⁷Al NMR whichelucidates the structural environment surrounding Al atoms which areembodied in various forms (Casey W H, “Large Aqueous Aluminum HydroxideMolecules”, Chem. Rev. 2006, 106 (1), pages 1 to 16).

There are two regions in a ²⁷Al NMR spectrum that represent Al nucleiwhich are octahedrally coordinated (0 ppm-60 ppm and tetrahedrallycoordinated (60 ppm-90 ppm). The octahedral region is exemplified by thehexa-aqua Al species, i.e. monomeric Al, which resonates sharply at 0ppm. The tetrahedral region is exemplified by sharp resonance at 62.5ppm from the Al₁₃ polyhydroxyoxoaluminum cation. Al₁₃ is composed of 12octahedrally coordinated Al atoms surrounded by one centrally-cited Alatom which is tetrahedrally coordinated. The Al₃₀ polyhydroxyoxoaluminumcation is essentially a dimer of the Al₁₃ polyhydroxyoxoaluminum cationand contains 2 tetrahedrally coordinated Al atoms which resonate at 70ppm.

It is known that ²⁷Al NMR spectroscopy may not fully elucidate thechemical composition of a partially neutralized Al salt solution, sincethere may be a variety of Al species that do not give rise to sharp andunambiguous resonance peaks. These species can be considered aseffectively NMR-invisible. Unless the ²⁷Al NMR spectroscopy is carriedout quantitatively, the relative concentration of these NMR-invisiblespecies cannot be determined and must be inferred from SECchromatography.

The state of the art discloses a number of methods for synthesizing andpurifying the Al₁₃ polyhydroxyoxoaluminum cation (for example Fu G, etal, “Aging Processes of Alumina Sol-Gels; Characterization of NewAluminum Polycations by ²⁷Al NMR Spectroscopy” Chem. Mater. 1991, 3(4),pages 602 to 610).

It is known that the Al₁₃ polyhydroxyoxoaluminum cation may be convertedto obtain the Al₃₀ polyhydroxyoxoaluminum cation by heating a solutionof the Al₁₃ polyhydroxyoxoaluminum cation (Roswell J et al, “Speciationand Thermal Transformation in Alumina Sols; Structures of thePolyhydroxyoxoaluminum Cluster [Al₃₀O₈(OH)₅₆(H₂O)₂₆]¹⁸⁺ and its δ-KegginMoieté”, J. Am. Chem. Soc. 2000, 122, pages 3777 to 3778; Chen Z et al,“Effect of thermal treatment on the formation and transformation ofKeggin Al₁₃ and Al₃₀ species in hydrolytic polymeric aluminumsolutions”, Colloids and Surfaces A: Physiochem. Eng. Aspects, 292(2007) pages 110 to 118; and Allouche L et al, “Conversion of Al₁₃Keggin ε into Al₃₀: a reaction controlled by aluminum monomers”,Inorganic Chemistry Communications, 6 (2003) pages 1167-1170).

Heating, an Al₁₃ solution is the only synthetic pathway to achievingAl₃₀ which has been described in the literature. As well as thereferences identified above, WO-A-2006/103092 and Shafran K L et al,“The static anion exchange method for generation of high purity aluminumpolyoxocations and monodisperse aluminum hydroxide nano-particles”, J.Mater. Chem., 2005, 15, pages 3415 to 3423, disclose the use of anion-exchange process to synthesize Al₁₃ to achieve greater than 90%purity, and disclose heating the thus-formed Al₁₃ solution to form Al₃₀.

Partial neutralization of Al salts have been shown to yield tracequantities of the polyhydroxyoxoaluminum cation detectable at 76 ppm by²⁷Al NMR. There is a need in the art for a high-yield synthetic route tothe polyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR. Thesmall quantities obtained, lack of purity, and lack of method of makinghas prevented science from isolating this polycation in sufficientquantity and purity so that its structure could be determined.

There is a need in the art for aluminum antiperspirant actives whichhave high antiperspirant efficacy.

There is also a need in the art for aluminum antiperspirant activeswhich have high stability.

There is also a need in the art for aluminum antiperspirant activeswhich have the combination of high antiperspirant efficacy and highstability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ²⁷Al NMR spectrograph of material 1 from the examples beforeheating.

FIG. 2 is a ²⁷Al NMR spectrograph of material 1 from the examples afterheating.

FIG. 3 is a ²⁷Al NMR spectrograph of material 2 from the examples beforeheating.

FIG. 4 is a ²⁷Al NMR spectrograph of material 2 from the examples afterheating.

BRIEF SUMMARY OF THE INVENTION

The present invention is based on modifying the composition from theinventors' earlier work, which was filed as PCT/US2010/55030 on 2 Nov.2011. It has been discovered that the Al₃₀ in antiperspirant salt can beconverted to a species of polyhydroxyoxoaluminum cation detectable at 76ppm by ²⁷Al NMR. This species also will elute at Peak 4 on as SECchromatogram.

The previous material can be aged for a sufficient time at sufficienttemperature to convert the Al₃₀. In one embodiment, the material can beaged at about 100° C. for a sufficient period of time, such as about 10days or greater, or about 30 days or greater. In another embodiment, thematerial can aged by supercritical heating in an isochoric reactionvessel or under hydrothermal reaction at sufficient temperature andtime, such as at 100° C. for 5 days. In another embodiment, the materialcan be aged at ambient conditions (such as 15° C. to 60° C.) for aperiod of time of several months, such as at least 6 months, to morethan one year.

The present invention accordingly provides antiperspirant activecomposition comprising an aluminum salt, the aluminum salt (i) having analuminum to chloride molar ratio of 0.3:1 to 3:1; and (ii) having aspecies of polyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷AlNMR that is present in a relative abundance on a ²⁷Al NMR spectrographthat is greater than any other polyhydroxyoxoaluminum cation detectableby ²⁷Al NMR.

In other embodiments, the species of polyhydroxyoxoaluminum cationdetectable at 76 ppm by ²⁷Al NMR is present in an amount that is amajority of a total amount of all species of polyhydroxyoxoaluminumcations detectable by ²⁷Al NMR. In other embodiments, the species ofpolyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR ispresent in an amount that is at least 50, 55, 60, 65, 70, 75, 80, 85,90, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999% of a total amountof all species of polyhydroxyoxoaluminum cations detectable by ²⁷Al NMR.

Optionally, the aluminum salt exhibits a SEC chromatogram having a SECPeak 4 area of at least 90% of a total area of Peaks 1, 2, 3, 4 and 5 inthe SEC chromatogram.

In this specification, the SEC chromatogram is measured using an aqueoussolution of the aluminum salt.

In some embodiments, the ²⁷Al NMR spectrum has a species distributionincluding at most 5% Al₁₃ polyhydroxyoxoaluminum cation in the speciesdetectable by ²⁷Al NMR within the aluminum salt. In some embodiments,the ²⁷Al NMR spectrum has a species distribution including no Al₁₃polyhydroxyoxoaluminum cation in the species detectable by ²⁷Al NMRwithin the aluminum salt. In some embodiments, the ²⁷Al NMR spectrum hasa species distribution including at most 5% Al_(m). Al_(m) comprising analuminum-and chloride-containing monomer, in the species detectable by²⁷Al NMR within the aluminum salt.

In some embodiments, the aluminum salt has an OH to Al ratio of at most2.6:1, and in other embodiments 2:1 to 2.6:1, optionally an OH to Alratio of 2:1 to 2.5:1, or 2.3:1 to 2.5:1.

The antiperspirant active composition may optionally further comprise abuffer, wherein a molar ratio of buffer to aluminum is at least 0.1:1.In other embodiments, the molar ratio is 0.1:1 to 3:1. The buffer may beat least one buffer chosen from an amino acid, betaine, and quat.Optionally, the buffer is an amino acid and a molar ratio of amino acidto aluminum is at least 0.1:1. In some embodiments, the amino acid isglycine.

In some embodiments, the composition has a SEC Peak 4 area of at least95% of a total area of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram.In some embodiments, the composition has a SEC Peak 3 area of less than5% of a total area of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram,and most preferably has no SEC Peak 3 area in the SEC chromatogram.

In some embodiments, the composition has a SEC Peak 5 area of less than5% of a total area of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram,and most preferably has no SEC Peak 5 area in the SEC chromatogram.

In some embodiments, the antiperspirant active composition has a SECPeak 4 area of 95 to 100%, no SEC Peak 3 area, and a SEC Peak 5 area offrom 0 to 5% of a total area of Peaks 1, 2, 3, 4 and 5 in the SECchromatogram.

The antiperspirant active composition may further comprise zirconium,and optionally a molar ratio of aluminum to zirconium is 5:1 to 10:1.

A method of making an antiperspirant active composition comprising:

-   -   I) heating an aqueous solution containing i) a first aluminum        salt containing an Al₃₀ polyhydroxyoxoaluminum cation and having        an aluminum to chloride molar ratio of 0.3:1 to 3:1, ii) an        inorganic salt, and iii) a buffer, wherein the buffer is at        least one of an amino acid, betaine, and quat and a molar ratio        of buffer to aluminum is at least 0.1:1, wherein the heating is        one of        -   a) at a temperature of 100° C. to 250° C. in an isochoric            reactor or under hydrothermal reaction for a time sufficient            to form a species of polyhydroxyoxoaluminum cation            detectable at 76 ppm by ²⁷Al NMR; or        -   b) at 100° C. at reflux for about 10 days or greater,            optionally about 30 days or greater to form a fourth            aluminum salt.

The present invention also provides a method of making an antiperspirantactive composition comprising:

-   -   I) heating an aqueous solution containing a first aluminum salt        having an aluminum to chloride molar ratio of 0.3:1 to 3:1 and a        buffer, wherein the buffer is at least one of an amino acid,        betaine, and quat and a molar ratio of buffer to aluminum is at        least 0.1:1, at a temperature of 50° C. to 100° C. for a period        of time of 1 hour to 6 hours to obtain a first aluminum salt        solution;    -   II) adding to the first aluminum salt solution an aqueous        solution of an inorganic base to obtain a second pH adjusted        aluminum salt solution having an OH:Al molar ratio of at most        2.6:1, or optionally 2:1 to 2.6:1, and a pH of 2 to 5;    -   III) heating the second pH adjusted aluminum salt solution at a        temperature of 50° C. to 100° C. for a period of time of at        least 6 hours to obtain a third aluminum salt solution        containing an Al₃₀ polyhydroxyoxoaluminum cation;    -   IV) heating the third aluminum salt solution at one of        -   a) at a temperature of 100° C. to 250° C. in an isochoric            reactor or under hydrothermal reaction for a time sufficient            to form a species of polyhydroxyoxoaluminum cation            detectable at 76 ppm by ²⁷Al NMR; or        -   b) at 100° C. at reflux for about 10 days or greater,            optionally about 30 days or greater;        -   to form a fourth aluminum salt; and    -   V) optionally adding an aqueous solution containing a zirconium        compound to the second pH adjusted aluminum salt solution to        thereby obtain a second pH adjusted aluminum-zirconium salt        solution having a molar ratio of aluminum to zirconium of 5:1 to        10:1.

The present invention also provides a method of making apolyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMRcomprising storing an aqueous solution containing i) the aluminum saltcontaining an Al₃₀ polyhydroxyoxoaluminum cation and having an aluminumto chloride molar ratio of 03:1 to 3:1, ii) an inorganic salt, and iii)a buffer, wherein the buffer is at least one of an amino acid, betaine,and quat, and a molar ratio of buffer to aluminum is at least 0.1:1 at atemperature of 15° C. to 60° C. for a period of time until thepolyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR that ispresent in a relative abundance on a ²⁷Al NMR spectrograph that isgreater than any other polyhydroxyoxoaluminum cation detectable by ²⁷AlNMR.

In some embodiments, the buffer is glycine. In some embodiments, theinorganic salt is at least one chloride salt chosen from calciumchloride, magnesium chloride, strontium chloride, barium chloride,stannous chloride, and yttrium chloride. In some embodiments, theinorganic base includes at least one member chosen from calciumhydroxide, magnesium hydroxide, strontium hydroxide, barium hydroxide,stannous hydroxide, yttrium hydroxide, calcium oxide, magnesium oxide,strontium oxide, barium oxide, stannous oxide, yttrium oxide, calciumcarbonate, magnesium carbonate, strontium carbonate, barium carbonate,stannous carbonate, and yttrium carbonate. Typically, the inorganic baseis calcium hydroxide. In some embodiments, the aluminum salt solutionhas an OH to Al molar ratio of 2.0:1 to 2.5:1 or 2.1:1 to 2.5:1.

In some embodiments, the first aluminum salt is an aluminum chloridecompound chosen from aluminum trichloride, aluminum chlorohexahydrate,aluminum dichlorohydmte, and aluminum monochlorohydrate. Optionally, thecomposition further comprises zirconium. The zirconium compound may beZrOCl₂.8H₂O or Oxo-Hexameric Zirconium-Octaamino Acid.

In some embodiments, the fourth aluminum salt has a SEC Peak 4 area ofat least 95% of a total area of Peaks 1, 2, 3, 4 and 5 in the SECchromatogram. In some embodiments, the fourth aluminum salt has a SECPeak 3 area of less than 5% of a total area of Peaks 1, 2, 3, 4 and 5 inthe SEC chromatogram, and preferably the fourth aluminum salt has no SECPeak 3 area in the SEC chromatogram. In some embodiments, the fourthaluminum salt has a SEC Peak 5 area of less than 5% of a total area ofPeaks 1, 2, 3, 4 and 5 in the SEC chromatogram.

In some embodiments, in step III) the period of time is at least 12hours, or in some embodiments at least 24 hours.

The present invention further provides the use of a heating step toconvert Al₃₀ polyhydroxyoxoaluminum cations in the species detectable by²⁷Al NMR within an aqueous aluminum salt solution into a species ofpolyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR, theaqueous aluminum salt solution i) having an aluminum to chloride molarratio of 0.3:1 to 3:1; ii) an inorganic salt, and iii) a buffer, whereinthe buffer is at least one of an amino acid, betaine, and quat, and amolar ratio of buffer to aluminum is at least 0.1:1; an OH:Al molarratio of at most 2.6:1, or optionally, 2:1 to 2.6:1; and the heatingstep is one of:

-   a) at a temperature of 100° C. to 250° C. in an isochoric reactor or    under hydrothermal reaction for a time sufficient to form a species    of polyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR;    or-   b) at 100° C. at reflux for about 10 days or greater, optionally    about 30 days or greater.

In some embodiments, the heating step converts all the Al₁₃polyhydroxyoxoaluminum cation species present in the aqueous aluminumsalt solution into the Al₃₀ polyhydroxyoxoaluminum cation species. Insome embodiments, the heating step reduces a SEC Peak 5 area in the SECchromatogram. Optionally, the period of time is at least 12 hours or, inother embodiments, at least 24 hours. In some embodiments, the buffer isglycine.

In some embodiments, the OH:Al molar ratio has been achieved by addingto the aqueous aluminum salt solution an inorganic base including atleast one member chosen from calcium hydroxide, magnesium hydroxide,strontium hydroxide, barium hydroxide, stannous hydroxide, yttriumhydroxide, calcium oxide, magnesium oxide, strontium oxide, bariumoxide, stannous oxide, yttrium oxide, calcium carbonate, magnesiumcarbonate, strontium carbonate, barium carbonate, stannous carbonate,and yttrium carbonate. Typically, the inorganic base is calciumhydroxide. Optionally, the OH to Al molar ratio is 2.0:1 to 2.5:1 or2.1:1 to 2.5:1.

In some embodiments, the aluminum salt is an aluminum chloride compoundchosen from aluminum trichloride, acidified aluminum chlorohexahydrate,aluminum dichlorohydrate, and aluminum monochlorohydrate.

In some embodiments, the heating increases the Al₃₀polyhydroxyoxoaluminum cation species in the ²⁷Al NMR spectrum from atleast 90% to at least 95% of the species detectable by ²⁷Al NMR withinthe aluminum salt.

In some embodiments, after the heating step the aluminum salt has a SECPeak 4 area of at least 95% of a total area of Peaks 1, 2, 3, 4 and 5 inthe SEC chromatogram. In some embodiments, after the heating step thealuminum salt has a SEC Peak 3 area of less than 5% of a total area ofPeaks 1, 2, 3, 4 and 5 in the SEC chromatogram, and preferably has noSEC Peak 3 area in the SEC chromatogram. In some embodiments, after theheating step the aluminum salt has a SEC Peak 5 area of less than 5% ofa total area of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram.

The present invention further provides an antiperspirant activecomposition including an aluminum salt produced by the method of theinvention or the use of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In this specification, the use of ²⁷Al NMR data is not quantitative butconsiders only NMR-visible Al species and in particular resonances at 0ppm, 62.5 ppm, 70 ppm, and 76 ppm. Octahedrally coordinated nuclei aredetected via ²⁷Al NMR. The Al monomer resonance at 0 ppm is octahedrallycoordinated. Octahedral bands in Al₁₃ and Al₃₀ are broad andoverlapping, so they're not useful when identifying Al species. Thebreadth of octahedral bands in Al₁₃ & Al₃₀ is due to structural andenvironmental variation. Because the Al nuclei in monomeric Al existstructurally in one form, the signal is narrow, and easily identified.Tetrahedrally coordinated nuclei in Al₁₃ and Al₃₀ also feature minimalvariation, which leads to narrow, identifiable NMR signals. ²⁷Al NMRdata do not indicate the amount of undetected Al embodied inNMR-invisible species.

When calculating, the relative amounts of Al embodied in compositionscontain ²⁷Al NMR visible species that have known structures, such asAl₁₃ and Al₃₀ polyhydroxyoxoaluminum cations, the tetrahedral resonancepeak of the aluminum is integrated and multiplied by a scaling factor toaccount for other octahedrally coordinated Al present in the structure.In the Al₁₃ polyhydroxyoxoaluminum cation, there is one tetrahedralresonance peak in the structure. In the Al₃₀ polyhydroxyoxoaluminumcation, there are two tetrahedral resonance peaks in the structure. Toconvert, the resonance from the Al₁₃ polyhydroxyoxoaluminum cation ismultiplied by 13, whereas the resonance from the Al₃₀polyhydroxyoxoaluminum cation is multiplied by 15. When the structure ofthe 76 ppm material is identified, a scaling factor can be determined.

For now, the amounts of each species of polyhydroxyoxoaluminum cation ina composition will be characterized by the relative abundance oftetrahedral aluminum resonance peaks on a ²⁷Al NMR spectrograph. Thismeans that the area of the tetrahedral aluminum resonance peak for apolyhydroxyoxoaluminum cation is compared to the area of the tetrahedralaluminum resonance peaks for other polyhydroxyoxoaluminum cations. The²⁷Al NMR spectrograph should be collected at sufficient enough fieldstrength so that all relevant signals can be integrated. One procedurefor operating a ²⁷Al NMR is described in the examples below. In thecurrent state of the art, the resonance frequency is at least 104.2 Mhzto provide a sufficient field strength.

The present invention is directed to antiperspirant active compositioncomprising an aluminum salt, the aluminum salt (i) having an aluminum tochloride molar ratio of 0.3:1 to 3:1; and (ii) having a species ofpolyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR that ispresent in a relative abundance on a ²⁷Al NMR spectrograph that isgreater than any other polyhydroxyoxoaluminum cation detectable by ²⁷AlNMR.

In certain embodiments, the species of polyhydroxyoxoaluminum cationdetectable at 76 ppm by ²⁷Al NMR is present in an amount that is atleast 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, 99.5,99.9, 99.99, or 99.999% of a total amount of all species ofpolyhydroxyoxoaluminum cation detectable by ²⁷Al NMR. In otherembodiments, the species of polyhydroxyoxoaluminum cation detectable at76 ppm by ²⁷Al NMR is present in an amount that is a majority of a totalamount of all species of polyhydroxyoxoaluminum cations detectable by²⁷Al NMR.

The species of polyhydroxyoxoaluminum cation detectable at 76 ppm by²⁷Al NMR can be made by heating an aqueous solution containing a lustaluminum salt containing an Al₃₀ polyhydroxyoxoaluminum cation andhaving an aluminum to chloride molar ratio of 03:1 to 3:1, ii) aninorganic salt, and iii) a buffer, wherein the buffer is at least one ofan amino acid, betaine, and quat, and a molar ratio of buffer toaluminum is at least 0.1:1, wherein the heating is one of

-   a) at a temperature of 100° C. to 250° C. in an isochoric reactor or    under hydrothermal reaction for a time sufficient to form a species    of polyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR;    or-   b) at 100° C. at reflux for about 10 days or greater, optionally    about 30 days or greater.

The reaction in the isochoric reactor is conducted at 100° C. to 250° C.As the temperature increases, the time need to convert Al₃₀polyhydroxyoxoaluminum cation to the polyhydroxyoxoaluminum cationdetectable at 76 ppm by ²⁷Al NMR decreases. Below are some examples oftemperature and time:

-   i) at 100° C. for about 5 days,-   ii) at 120° C. for about 12 hours, or-   iii) at 150° C. for about 20 minutes.

The inorganic salt and buffer help to stabilize the species ofpolyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷Al NMR. Incertain embodiments, the inorganic salt is at least one chloride saltchosen from calcium chloride, strontium chloride, barium chloride,magnesium chloride, stannous chloride, and yttrium chloride. In oneembodiment, the salt is calcium chloride. In certain embodiments, thebuffer is glycine. In certain embodiments, the inorganic salt is calciumchloride and the buffer is glycine.

The present invention can provide an antiperspirant active compositionhaving a high SEC peak 4 in aqueous solution. The composition isobtained by a stepwise procedure to neutralize aluminum chloride in asolution (optionally buffered) using inorganic bases. In someembodiments, the antiperspirant active compositions obtained by thisstepwise procedure include aluminum salts having an aluminum to chloridemolar ratio of 0.3:1 to 3:1, optionally, the aluminum salt exhibits aSEC chromatogram having a SEC Peak 4 area of at least 90% of a totalarea of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram in aqueoussolution. The composition may optionally include zirconium.

The description below describes methods of obtaining an Al₃₀polyhydroxyoxoaluminum cation containing composition.

The Al₃₀ containing compositions may be made in a variety of waysinvolving a stepwise procedure to neutralize aluminum chloride insolution (optionally buffered) using inorganic basic salts. Theprocedure generally includes the step of heating an aqueous solutioncontaining an aluminum chloride compound (optionally with a bufferagent) at a temperature of 50° C. to 100° C., optionally 50° C. to 95°C., for a period of time of 1 hour to 6 hours. The heating may be understirring, such as vigorous stirring, or under reflux. In one suchembodiment, an aqueous solution containing an aluminum chloride compoundand a buffer agent is heated at a temperature of 75° C. to 95° C. toreflux for a period of time of 2 hours to 4 hours. In one embodiment,the temperature is 95° C. under vigorous stirring for a period of timeof 2.5 hours.

To adjust the pH of the aluminum salt solution, an aqueous solution ofan inorganic base is added to the heated solution to thereby obtain a pHadjusted aluminum salt solution having a hydroxide to aluminum molarratio of 1:1 to 4:1, and a pH of 2 to 5. In one such embodiment, thehydroxide to aluminum molar ratio of 2:1 to 3:1. In another suchembodiment, the hydroxide to aluminum molar ratio is 2.1:1 to 2.6:1.

In one embodiment, the inorganic base can be at least one base chosenfrom metal hydroxides, calcium hydroxide, magnesium hydroxide, strontiumhydroxide, barium hydroxide, stannous hydroxide, yttrium hydroxide,calcium oxide, magnesium oxide, strontium oxide, barium oxide, stannousoxide, yttrium oxide, calcium carbonate, magnesium carbonate, strontiumcarbonate, barium carbonate, stannous carbonate, and yttrium carbonate.

Optionally, a buffer can be included. Buffers that can be used can bechosen from amino acids, such as glycine, and betaine, such as betainemonohydrate, or quats. The buffer to aluminum molar ratio in certainembodiments can be at least 0.1:1, or 0.1:1 to 3:1. In anotherembodiment, the buffer to aluminum molar ratio is 0.1:1 to 2:1.

In one embodiment, the inorganic base is calcium hydroxide. In one suchembodiment, the addition of calcium hydroxide provides an aqueoussolution having a Ca(OH)₂:glycine molar ratio of at least 0.1:1.

When a buffer is absent, significant Peak 3 species in the SECchromatogram begin to form when the total Al concentration is above0.2M. When a buffer is present, the total Al concentration can reach upto 2.5M while maintaining a predominant Peak 4 in the SEC chromatogram.In one embodiment, an aqueous aluminum chloride salt solution isbuffered with glycine and held at 50° C. to 95° C. under vigorousstirring for a period time of 1 to 6 hours. To the heated solution, anaqueous solution of an inorganic base is added dropwise over a period oftime of 1 to 3 hours while maintaining the aluminum-glycine solution at50° C. to 95° C. under vigorous stirring. In one such embodiment, thesolution has a glycine to aluminum molar ratio of 1.5. In another suchembodiment, the solution has a glycine to aluminum molar ratio of 0.5.

In some embodiments, a zirconium salt may also be added to the pHadjusted aluminum salt solution. In one other such embodiment, the molarratio of Al:Zr is 5:1 to 10:1. The zirconium salt may be simple Zrsalts: ZrOCl₂.8H₂O or Oxo-Hexameric Zirconium-Octaamino Acid. In onesuch embodiment, the molar ratio of Al:Zr is 8. In another suchembodiment, the molar ratio of Al:Zr is 7. In one other such embodiment,the molar ratio of Al:Zr is 9.

For the above methods, the aluminum chloride salt and inorganic base maybe obtained from a variety of sources. In one embodiment, the aluminumchloride salt includes aluminum trichloride, acidified aluminumchlorohexahydrate, aluminum dichlorohydrate, and aluminummonochlorohydrate. In one such embodiment, the aluminum chloride salt isaluminum chlorohexahydrate.

The present invention provides for aluminum antiperspirant activecompositions and/or aluminum-zirconium antiperspirant activecompositions having high levels of low molecular weight Al and Zrspecies. The high levels of low molecular weight Al and Zr species isreflected in a SEC trace that has an intense Peak 4 and low Peaks 1, 2,3 and 5. The polymerization of the antiperspirant actives in aqueoussolutions and the correspondent gelation process were followed bymonitoring the molecular weight profile of the polyoxohalides in time bySEC. The relative retention time (“Kd”) for each of these peaks variesdepending on the experimental conditions, but the peaks remain relativeto each other. The SEC data for the examples was obtained using an SECchromatogram using the following parameters: Waters®600 analytical pumpand controller, Rheodyne® 77251 injector, Protein-Pak® 125 (Waters)column, Waters 2414 Refractive Index Detector. 5.56 mM nitric acidmobile phase, 0.50 ml/min flow rate, 2.0 microliter injection volume.Data was analyzed using Waters® Empower software (Waters Corporation,Milford, Mass.). The concentration of the antiperspirant in aqueoussolution does not affect the retention time in the machine.

The design of modern antiperspirant (AP) salts aims at actives with highlevels of low molecular weight Al and Zr species, which is reflected ina SEC trace that has intense Peak 4 and low Peaks 1, 2, and 3, andoptionally low Peak 5. Throughout the present study, the levels of thespecies corresponding to these peaks are estimated based on thefollowing ratios (or percentages):

${f_{Pi} = {{\frac{Pi}{\sum{Pj}}i} = 1}},2,3,4,{5;}$ j = 2, 3, 4, 5where f_(Pi) is the fraction of peak i, and Pi or Pj are the intensityof peaks Pi or Pj, respectively. The amount of low molecular weight Alspecies will be correlated with the fraction, f_(P4), or percentage,f_(P4)×100, of SEC-Peak 4. In brief, a preferred antiperspirant saltwould have a very low f_(P1), f_(P2), f_(P3), and/or f_(P5), and a highf_(P4).

In certain embodiments, the ratio of Peak 4 to Peak 3 is at least 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60,70, 80, 90, 100, or any number up to infinity. Preferably, Peak 3 is solow as to be undetectable.

In one embodiment, an aluminum salt and/or aluminum-zirconium salt, inaqueous solution, exhibit a SEC profile wherein the SEC Peak 4 to Peak 3intensity ratio is even as high as infinity, because the Peak 3 isundetectable. In some embodiments, the percentage of SEC Peak 4 of atotal area of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram is: atleast at least 90%; at least 95%, or 95 to 100%. In another suchembodiment, the SEC Peak 4 area is 100%.

In another embodiment, the aluminum salt and/or the aluminum-zirconiumsalt, in aqueous solution, exhibits a SEC profile which exhibits lowpercentage of SEC Peak 3. In such embodiments, the composition has thepercentage of SEC Peak 3 area of a total area of Peaks 1, 2, 3, 4 and 5in the SEC chromatogram is: less than 5%; less than 2%; less than 1%;less than 0.9%: less than 0.8%; less than 0.7%; less than 0.6%; of lessthan 0.5%; less than 0.4%; less than 0.3%; less than 0.2%; or less than0.1%. In another such embodiment, the composition has no SEC Peak 3area.

In another embodiment, the aluminum salt and/or the aluminum-zirconiumsalt, in aqueous solution, exhibits a SEC profile which exhibits lowpercentages of SEC Peak 5. In such embodiments, the percentage of SECPeak 5 area of a total area of Peaks 1, 2, 3, 4 and 5 in the SECchromatogram is: less than 5%; or less than 1%. In another suchembodiment, the composition has no SEC Peak 5 area.

In other embodiments, the aluminum salt and/or the aluminum-zirconiumsalt, in aqueous solution, exhibits a SEC profile which exhibits a lowpercentage of SEC Peak 1 and a low percentage of SEC Peak 2. In suchembodiments, the percentage of SEC Peak 1 area of a total area of Peaks1, 2, 3, 4 and 5 in the SEC chromatogram is less than 5%; less than 2%;or less than 1%, or the salt has no SEC Peak 1 area. In otherembodiments, the percentage of SEC Peak 2 area of a total area of Peaks1, 2, 3, 4 and 5 in the SEC chromatogram is less than 5%; less than 2%or less than 1%; or the salt has no SEC Peak 2 area. Preferably, thesalt has no Peak 1 area and no Peak 2 area. More preferably, the salthas no Peak 1 area, no Peak 2 area and no Peak 3 area. Yet morepreferably, the salt has no Peak 1 area, no Peak 2 area, no Peak 3 areaand no Peak 5 area.

The aluminum antiperspirant active compositions and/oraluminum-zirconium antiperspirant active compositions may be used in avariety of antiperspirant products. If the product is used as a solidpowder, the size of the particles of antiperspirant active of theinvention can be any desired size, and may include conventional sizessuch as in the range of 2 to 100 microns, with selected grades having anaverage particle size of 30-40 microns; finer sized grades having anaverage particle size distribution of 2-10 microns with an average sizeof 7 microns as made by a suitable dry-grinding method; and micronizedgrades having an average particle size of less than or equal to 2microns, or less than or equal to 1.5 microns.

The compositions of this invention may be used to formulateantiperspirants having improved efficacy. Such antiperspirants includesolids such as sticks and creams (creams sometimes being included in theterm “soft solid”), gels, liquids (such as are suitable for roll-onproducts), and aerosols. The forms of these products may be suspensionsor emulsions. These antiperspirant actives can be used as theantiperspirant active in any antiperspirant composition. Examples offormulations can be found in WO20091076591.

The present invention is exemplified by the following non-limitingExamples.

EXAMPLES

Two materials prepared in accordance with PCT/US2010/55030 are provided.The materials are aqueous systems that contain the glycine buffer andthe calcium chloride byproduct of the manufacturing process.

The raw integration values for ²⁷Al NMR spectroscopy peaks for thesematerials are listed below in Table 1, and Table 2 shows the relativeabundance. The materials are analyzed by taking a 1 M solution anddiluting in a 1:4 ratio using D₂O. The final Al concentration for allsamples is 0.25M. The samples are analyzed at a ²⁷Al resonance frequencyof 104.2 MHz at 90° C. A coaxial insert containing NaAlO₂ is included toprovide a reference resonance peak at 80 ppm. The instrument collects1500 transients, with a pulse width of 6.4 μs and a delay time of 2seconds. The data for the relevant peaks are shown in the tables below.The full spectrographs can be seen in FIGS. 1 to 4.

Materials 1 is held at reflux for 30 days at 100° C. Material 2 issubjected to 100° C. for 5 days in an isochoric reaction vessel. Forcomparative purposes, the following discussion relates only with therelative integrations instead of raw data.

For Material 1, the Al₃₀ signal (encompassing 96.10% of the totalvisible tetrahedral Al) is converted to a signal at 76 ppm (97.76% TdAl). Also, the amount of Al₁₃ is reduced from 1.90% to 2.24%.

For Material 2, the Al₃₀ signal at 70 ppm (encompassing 98.44% of thetotal visible tetrahedral Al) is converted to a signal at 76 ppm (99.37%Td Al). Also, the amount of Al₁₃ is reduced from 1.56% to 0.63%.

TABLE 1 Total Visible Material 76 ppm 70 ppm 63 ppm T_(d) Al Material 1untreated None detected  906.11 36.75 942.86 Material 1 treated 1054.37None detected 24.15 1078.52 Material 2 untreated None detected 1581.9725.09 1611.06 Material 2 Treated 1453.69 None detected 9.20 1462.89

TABLE 2 Relative Abundance % Material 76 ppm 70 ppm 63 ppm Material 1untreated 0 96.10 3.90 Material 1 treated 97.76 0 2.24 Material 2untreated 0 98.44 1.56 Material 2 Treated 99.37 0 0.63

As used throughout, ranges are used as shorthand for describing each andevery value that is within the range. Any value within the range can beselected as the terminus of the range. In addition, all references citedherein are hereby incorporated by referenced in their entireties. In theevent of a conflict in a definition in the present disclosure and thatof a cited reference, the present disclosure controls.

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. The amounts given are based on the active weightof the material.

What is claimed is:
 1. A method of making an antiperspirant activecomposition comprising: I) heating an aqueous solution containing i) afirst aluminum salt containing an Al₃₀ polyhydroxyoxoaluminum cation andhaving an aluminum to chloride molar ratio of 0.3:1 to 3:1, ii) aninorganic salt, and iii) a buffer, wherein the buffer is at least one ofan amino acid, betaine, and quat, and a molar ratio of buffer toaluminum is at least 0.1:1, wherein the heating forms a fourth aluminumsalt and is one of a) at a temperature of 100° C. to 250° C. in anisochoric reactor or under hydrothermal reaction for a time sufficientto form a species of polyhydroxyoxoaluminum cation detectable at 76 ppmby, ²⁷Al NMR; or b) at 100° C. at reflux for about 10 days or greater.2. A method of making an antiperspirant active composition comprising:I) heating an aqueous solution containing a first aluminum salt havingan aluminum to chloride molar ratio of 0.3:1 to 3:1 and a buffer,wherein the buffer is at least one of an amino acid, betaine, and quat,and a molar ratio of buffer to aluminum is at least 0.1:1, at atemperature of 50° C. to 100° C. for a period of time of 1 hour to 6hours to obtain a first aluminum salt solution; II) adding to the firstaluminum salt solution an aqueous solution of an inorganic base toobtain a second pH adjusted aluminum salt solution having an OH:Al molarratio of at most 2.6:1; III) heating the second pH adjusted aluminumsalt: solution at a temperature of 50° C. to 100° C. for a period oftime of at least 6 hours to obtain a third aluminum salt solutioncontaining an Al₃₀ polyhydroxyoxoaluminum cation; IV) heating the thirdaluminum salt solution to form a fourth aluminum salt at one of a) at atemperature of 100° C. to 250° C. in an isochoric reactor or underhydrothermal reaction for a time sufficient to form a species ofpolyhydroxyoxoaluminum cation detectable at 76 ppm by ²⁷AI NMR; or b) at100° C. at reflux for about 10 days or greater; and V) optionally addingan aqueous solution containing a zirconium compound to the second pHadjusted aluminum salt solution to thereby obtain a second pH adjustedaluminum-zirconium salt solution having a molar ratio of aluminum tozirconium of 5:1 to 10:1.
 3. The method of claim 1, wherein theinorganic salt is at least one chloride salt chosen from calciumchloride, strontium chloride, barium chloride, and yttrium chloride. 4.The method of claim 1, wherein the buffer is glycine.
 5. The method ofclaim 2, wherein the buffer is glycine.
 6. The method of claim 1,wherein the inorganic salt is calcium chloride and the buffer isglycine.
 7. The method of claim 1, wherein heating in the isochoricreactor or under hydrothermal reaction is one of i) at 100° C. for about5 days, ii) at 120° C. for about 12 hours, or iii) at 150° C. for about20 minutes.
 8. The method of claim 2, wherein heating in the isochoricreactor or under hydrothermal reaction is one of i) at 100° C. for about5 days, ii) at 120° C. for about 12 hours, or iii) at 150° C. for about20 minutes.
 9. The method of claim 1, wherein the fourth aluminum saltexhibits a SEC chromatogram having a SEC Peak 4 area of at least 90% ofa total area of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram.
 10. Themethod of claim 2, wherein the fourth aluminum salt exhibits a SECchromatogram having a SEC Peak 4 area of at least 90% of a total area ofPeaks 1, 2, 3, 4 and 5 in the SEC chromatogram.
 11. The method of claim2, wherein the inorganic base includes at least one member chosen fromcalcium hydroxide, strontium hydroxide, barium hydroxide, calcium oxide,strontium oxide, barium oxide, calcium carbonate, barium carbonate,strontium carbonate, yttrium hydroxide, yttrium oxide, and yttriumcarbonate.
 12. The method of claim 11, wherein the inorganic, base iscalcium hydroxide.
 13. The method of claim 2, wherein the second pHadjusted aluminum salt solution has an OH to Al molar ratio of 2:1 to2.5:1.
 14. The method of claim 2, wherein the first aluminum salt is analuminum chloride compound chosen from aluminum trichloride, aluminumchlorohexahydrate, and aluminum dichlorohydrate.
 15. The method of claim2, wherein the composition further comprises zirconium and step V) ispresent in the method.
 16. The method of claim 15, wherein the zirconiumcompound is at least one of ZrOCl₂.8H₂O and Oxo-HexamericZirconium-Octaamino Acid.
 17. The method of claim 1, wherein the ²⁷AlNMR spectrum has a species distribution including at most 5% Al₁₃polyhydroxyoxoaluminum cation in the species detectable by ²⁷Al NMRwithin the fourth aluminum salt.
 18. The method of claim 2, wherein the²⁷Al NMR spectrum has a species distribution including at most 5% Al₁₃polyhydroxyoxoaluminum cation in the species detectable by ²⁷Al NMRwithin the fourth aluminum salt.
 19. The method of claim 1, wherein thefourth aluminum salt has a SEC Peak 4 area of at least 95% of a totalarea of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram.
 20. The methodof claim 2, wherein the fourth aluminum salt has a SEC Peak 4 area of atleast 95% of a total area of Peaks 1, 2, 3, 4 and 5 in the SECchromatogram.
 21. The method of claim 1, wherein the fourth aluminumsalt has a SEC Peak 3 area of less than 5% of a total area of Peaks 1,2, 3, 4 and 5 in the SEC chromatogram.
 22. The method of claim 2,wherein the fourth aluminum salt has a SEC Peak 3 area of less than 5%of a total area of Peaks 1, 2, 3, 4 and 5 in the SEC chromatogram. 23.The method of claim 2, wherein the third aluminum salt has a SEC Peak 5area of less than 5% of a total area of Peaks 1, 2, 3, 4 and 5 in theSEC chromatogram.
 24. The method according to claim 2, wherein in stepIII) the period of time is at least 12 hours.